1. Field of the Invention
This invention relates to improvements in the manufacturing of abrasive grinding wheels.
2. Prior Art
The concept of utilizing a revolving surface for frictional or impact removing of rough spots on various items such as weldments, concrete surfaces, machine work, and the like is well known. The U.S. Pat. No. 3,081,584 granted Mar. 19, 1963 to Robert A. Bullard, discloses a conventional abrasive wheel presently in commercial use. This abrasive wheel consists basically of a central base member to provide connection to a portable hand grinder or other machine for supplying the motive force and a disc member attached to the central base member. The disc member has usually assumed the form of a screen impregnated with an abrasive and a bonding agent.
The abrasive wheel of the Bullard patent utilizes a central mounting member with a considerable flange for providing sufficient surface to permit a fastening of the abrasive disc onto the central member by means of an epoxy resin cement. To further insure a sufficient bonding between the central mounting member and the abrasive disc, the tubular portion of the central mounting member that extends through the abrasive disc is generally "ball swaged" to provide a counter sunk portion of the tubular projection against the lower surface of the abrasive disc. Thus, the manufacturing process of the presently accepted abrasive wheel requires a two-step process for joining an abrasive disc to a metallic central mounting member. This process includes the step of adhering by an epoxy resin the flange of the central mounting member to the disc and further the step of mechanically deforming the metallic central member by countersinking or "ball swaging" the central mounting member onto the lower surface of the abrasive disc. Generally the epoxy material must be cured before the abrasive wheel is capable of use.
Another form of an abrasive wheel used for "snagging" provides a replaceable disc having a central hole which is mounted by a coaction of washers or clamps on either side of the disc onto a grinder machine. Vibrational problems in loosening the washers and clamps have been a problem in utilizing this form of abrasive wheel. Likewise a considerable amount of time and effort must be utilized by the operator in mounting the abrasive wheel on the grinder or changing an abrasive disc.